(A) Counts of TdTomato+ cells in each raphe nucleus of Tph2cKO mice did not differ from controls (n = 2 mice/genotype). Data are represented as mean ± SEM. (B) Comparable Tph2 knock-down in Tph2cKO and Lmx1bcKO mice. Scale bars, 100 µm. (C) Cell counts of residual Tph2+ neurons in Tph2cKO and Lmx1bcKO mice expressed as a percentage (n = 2 mice/genotype). Data are represented as mean ± SEM. (D) Immunolabeling shows 5-HT was severely reduced in Tph2cKO mice. Scale bars, 100 µm. (E) Coronal forebrain sections showing no deficits of TdTomato+ axon densities in Tph2cKO hippocampus, PVT, and cortex (n = 3 mice/genotype). LSM, lacunosum moleculare; DG, dentate gyrus; CA1 of hippocampus. Scale bars, 100 µm (PVT, cortex); 200 µm (hippocampus). (F) Co-immunolabeling for Tph2 and TdTomato in medullary neurons. Tph2 expression was severely reduced in medullary neurons of Tph2cKO mice. Scale bars, 50 µm. (G) No deficits of TdTomato+ axons were present throughout the Tph2cKO spinal cord (n = 3 mice/genotype). Scale bars, 200 µm.